Difference between Sap wood and Heart wood (Alburnum vs Duramen)

Sap wood is the functional, conducting part of the wood whereas heart wood is the non functional, non conducting part of the wood.  
Definition - Sap wood and Heart wood
Definition Sap wood:  Light coloured outer region of secondary wood performing the function of conduction of sap. Sap wood is also known as Alburnum
Definition Heart wood: Hard and dark coloured central region of secondary wood, which is unable to conduct the sap. Heart wood is also known as Duramen.

Sap wood vs Heart wood (Alburnum vs Duramen)

Sap wood
1. The outer region of the old trees forms the sap wood
2. It is also called as alburnum
3. it is soft and not durable
4. It is light coloured and formed of living cells
5. Vessels are not blocked by tyloses
6. The function of this region is conduction of water and nutrients and also storage of food

Heartwood
1. The central region of the old trees forms the Heart wood
2. It is also called as duramen
3. it is hard and durable
4. It is dark coloured due to the deposition of various substances
5. Vessels are blocked by tyloses with various deposits
6. The function of this region is mechanical support